Intravenous Suitability Studies of Commonly Used Oxacillin Sodium Solutions in the ACCUFUSER® Infusion Device

Our study compares two commonly used solutions of oxacillin sodium, 5.0 mg/mL in either 0.9% sodium chloride (NS) or 5% dextrose water (D5W), for their continued suitability for IV usage, and stability of active compound over time, when stored at two different controlled temperatures for six weeks. Both solutions were stored in an intravenous infusion device commercially available as Accufuser® and kept at a continuously maintained temperature of either 4 ± 2?C (CT) or 25 ± 2?C (RT). Suitability for IV administration was assessed by measuring changes in macrographical transparency and pH over time, and drug stability was assessed by measuring changes in oxacillin concentration over time using high-performance liquid chromatography (HPLC). After 6 weeks, concentrations of oxacillin were unchanged in the CT solutions, while both RT solutions showed significant decreases in the concentration of oxacillin after only two weeks. Final concentration compared to starting concentrations after 6 weeks at RT, were 36.57% in NS, while virtually no oxacillin was detectable in D5W. Also pH measurements showed a slight decrement at 2 weeks with RT, and at 6 weeks, there was a significant change in pH in both NS and D5W at RT. There was no significant change in color, transparency or appearance after 6 weeks in any of the oxacillin solutions stored in the Accufuser® infusion device. In summary, two commonly used IV solutions for oxacillin administration(5 mg/mL in NS or D5W) stored ready to use in the Accufuser® showed significant changes over time when maintained at RT, that would make the solutions inappropriate for therapeutic use. Both solutions when maintained in CT were not significantly altered and continued to be appropriate in pH and drug concentration for IV therapy. This suggests that ready-to-use solutions of oxacillin sodium in the Accufuser® infusion device can be kept at CT for up to 6 weeks safely but should not be stored at RT due to loss of potency and changes in pH.